Our Heater Buddy works very well! We got it during our PopUp days, but have kept it as emergency heat ever since. It will heat the camper with no problem. The propane lasts surprisingly long. How long, depends on how hot you want your living area. Just keep a window cracked to allow some oxygen into the room with the heater.
Ben and Doreen
Home Away From Home - 2017 PT Crusader 315RST
TV - 2008 F250 Lariat 4X4 6.4 Diesel
42 nights camping in 2015
57 nights so far in 2016 (a record for us, but Still Not Enough!)